I am only 2 months ahead of you in knowledge.
1) look at the tech section - clutching. tells you everything about what to do, and why.
2) mods are easy.
a) primary spring - take the 8 small bolts off and pull the cover off, cover is under some spring preload, just ease each of the last 4 bolts off a little at a time to not torque the clutch bushing sideways.replace the spring with WWW (3 white stripes).
b) clutch weights - I borrowed a clutch puller and poped the clutch off, but can be done on the sled - jsut don't drop any of the small washers on the weight shafts - easier to pop the clutch with the tool ( really long bolt with pointed end, remove clutch bolt, screw this one in until POP!!!!.
each weight comes off with small (about 3/16 size) bolts and shafts with washers.
weight comes off, and you can start to drill a hole in the inner rivet a little smaller than the weight hole. this weakens the rivet, then pop it out with a hammer and small punch
insert new rivet, and smash with a hammer. clean with hot soapy water, air dry thoroughly and reassemble, noteing alignment x's for balance. torque bolt to 80 ft-lbs,( sets taper fit) backoff, then retorque to 45 ft-lbs?
c) helix
back off three nuts equally. place a wrench or something behind the secondary so it doesn't spread apart while you try to hold things.
spring has some windup. just hold on decent and pull off studs slowly and back off windup ( about 60 degrees of windup)
replace helix, and wind to 70 degrees ( look at numbers on sheeve, and helix. and place ends of springs into correct hole numbers. make a combination addition to 7 ( = 70 degrees) ie. 1 and 6, . wind up to next bolts and assemble
d) go beat some skidoos
if you know what a metric crescent wrench is, then you will have no trouble.
Ramb